France's attempts to produce a staged thermonuclear weapon came to fruition with Canopus, it was also the largest French atmospheric test. Like most of the French tests, the three tonne device was suspended from a balloon. The top of the mushroom cloud reached an altitude of 23,400 meters, while the base reached an altitude of 14,500 meters. The cloud drifted to the north-east and fallout was detected on the atolls of Pukarua, Tureia, and Reao. The device used a lithium-6 deuteride secondary jacketed with HEU that caused massive contamination of the atoll, requiring it to be quarantined for six years. The device was weaponised, entering the stockpile in 1977 as the TN-60 with a 1 megaton nominal yield. These warheads were deployed on the Redoutable class ballistic missile submarines as well as on the land based SSBS S3 missiles.